Rosemary' Baby is not merely a sophisticated horror film. The horror is only one aspect of a complex statement frightening in its relevance. Based on the novel by Ira Levin, the film remains extraordinarily faithful to its literary source. But Polanski deserves the credit for re-creating the meaning in visual terms. The film is about a girl who is trapped in a reality which she cannot believe. She must choose between not believing what appears to be real or believing what cannot be real. The irony is that in this film, Rosemary finally believes the fantastic because Polanski gives it the texture of an undeniable reality, however bizarre.

The story takes the traditional Christ myth and dresses it an its equally traditional Satanic disguise. The film's myth parallels the New Testament, with the divine figure as father of the child, Rosemary as the chosen vessel, the starting of the new era with the birth of the messiah, and the adoration of the child. It treats the myth in such a way that we are forced to accept its literal truth. Yet at the same time we the audience cannot accept what is being presented as real, because for centuries we have believed that the birth of the anti-christ is a detestable lie. Yet the film gives us evidence for its truth that is more convincing than any evidence on which Christian belief is based. The film is frightening because it forces us to examine the kinds and bases of belief. We confront the idea that the Christian myth is certainly no more believable than its mirror image, and possibly less so. And beyond this, we are also forced to realise that our mode of believing in Christianity is quite different from the one with which we perceive 'real' things. (p. 17)

[There is] a merging of competing mythologies in the film's imagery. In the extraordinarily powerful scene where Rosemary conceives the Son of Satan, there is a merging of images from at least three mythologies: Satan and the witches from the demonic, the Pope and Michelangelo's creation of Adam from traditional Christianity, and the Kennedyesque yachting captain from the modern myth of power. The images in Rosemary's dream are constantly transformed from one to the other. For example, Guy's face dissolves into the demon, and Hutch assumes the role of Pope. These mergings of the various myth figures are further complicated by three modes of reality in the scene itself. Are these images Rosemary's dream, a half-drugged waking vision, or the fantastic reality of the witches' coven? Ironically, the events which trigger the uncertain reality of Rosemary's response are just as fantastic as the images themselves. Rosemary's scream that this is real, and the marks on her body the next morning, attest to their undeniable reality. That Rosemary has responded to them with the mixing of the three myths shows their interchangeability. As modes and myths merge in these ways, the film insists that we believe or disbelieve them all….

The film has forced us to face two things. First of all we claim to assign belief to our myths; yet if we do so, it is a different kind of belief than that which we assign to 'reality'. But our desire to hold belief is so powerful that under its pressure we can accept anything. (p. 19)